Tiger Woods keeps telling us over and over again he has plenty of time left in his career to catch Jack Nicklaus’ record of winning 18 major championships. Nicklaus won his last major when he captured the 1986 Masters at age 46. Since Woods is 36, his math says he still has 40 major championship appearances to win four.

Maybe there’s some logic in that outlook. Maybe it’s just wishful thinking, especially if you saw Woods labor around Bethpage Black the way he did yesterday afternoon.

Woods said he woke up with a sore back after sleeping on a soft hotel bed and knew on the practice range he was in for some discomfort during the second round of the Barclays. But as the round progressed he began to look closer to 56 than 36.

Give Woods credit for gutting it out. After suffering bogeys on his first two holes, he somehow managed a 2-under 69 to stand 5-under for the tournament. He trails co-leaders Nick Watney and Sergio Garcia by three shots heading into today’s third round. Woods expects to be “ready.”

That might be wishful thinking, too. If spending some time in the sports medicine trailer and sleeping on the floor of his hotel room will resolve his issues, God bless him. But there’s also a good chance Woods could spend the rest of weekend squatting and bending like Fred Couples.

The Black, with its hills and elevated greens, isn’t the easiest walk even for the fittest of men. Playing the course with a sore back is painful to watch.

Woods’ discomfort yesterday was obvious. Watching him squat down to place his ball on the green was filled with suspense as he kept his back straight while slowly bending his knees. Retrieving the ball out of the cup was an even bigger chore. He would extend one leg all the way back and slowly lower his body and gingerly pull the ball out of the hole. Between shots he would twist and turn or stretch his back while holding onto his golf bag.

It looked as if Woods broke his back on his tee-shot at the par-4 10th hole, where he released his club after the swing and winced in obvious pain. Then at the par-4 12th, Woods hit his drive into the bunker left of the fairway. As he descended down the slope toward the sand, his feet slipped. He landed in the sand with a thud, jarring his back. “That didn’t feel good at all,” he said.

Still, he downplayed his issues and wouldn’t compare it to the 2008 U.S. Open at Torrey Pines where he played on a knee that required reconstructive surgery the next week.

“There’s a difference between being in pain and injured,” Woods said. “This is just a little bit of pain. That was an injury.”

Nonetheless, anytime Woods is hobbled is cause for concern. He has already had four surgeries to his left knee. He also missed the 2011 U.S. Open with a sprained knee and a sprained left Achilles tendon.

This year, he has often talked about how being pain free has finally allowed him to practice more than in the past and how it is a big factor why he is a three-time winner on tour.

But as anyone of age can attest, once you hit age 35, it becomes more difficult to stay pain free. Woods even admitted, “It’s harder to recover,” but insisted he’s stronger and just as flexible as ever.

If this were a major championship, Woods’ back issues might be more alarming. The FedEx Cup is a four-tournament venture, giving him plenty of time for recovery and treatment along the way.

Still, the barking in his lower back yesterday is a clear signal that dealing with injuries will continue to be part of his career. What Woods must hope is they don’t shorten it and whittle his opportunities at catching Nicklaus.